# Can spacetime tear/break?

1. Oct 9, 2012

### r.hackett

The concept of spacetime ripping or breaking (down) is common in science fiction, but does it have any basis in real physics? Inside the singularity of a Black Hole, it seems that spacetime is stretched infinitely by gravity (conjecture, but a common belief, right?), but could it be possible that spacetime breaks down in some way at a certain point, possibly causing information to be lost forever?

I feel that it may not even be a meaningful question in reality (i.e. does it even make sense to assume that spacetime could do anything resembling tearing or breaking?), but I am curious of people's opinions or insight in to this.

edit:
Of course,this is all in the context of Einstein's Theory of Relativity (referring to "spacetime").

2. Oct 10, 2012

### twofish-quant

Some.

First a bit of definition. There is a branch of math called topology which is the study of how things behave when you try to bend them. You can bend a cube into a sphere, so they are in the same topological group. You can't bend a cube into a donut, so that's a different topological group.

There's an entire complicated branch of mathematics devoted to figuring out if you can bend thing A into thing B without ripping something apart.

So the question you are asking is whether you can change the topological group of space-time. And the answer is .....

We aren't sure....

There *are* solutions of GR in which space-time "rips" but these involve situations that we think aren't possible (i.e. you can rip a hole in space time with negative mass). Also weird things that no one understands at the singularity of black hole.

Also "space-time" is a mathematical tool. We aren't sure if it's the right mathematical tool to be use in the theory of everything.

Yes. It's possible. That's problem. We don't know what happens so pretty much anything is possible. It's possible that information gets destroyed at the singularity. It's also possible that it doesn't.

It makes sense. There is an entire branch of mathematics devoted to this. We don't know the answers, but we can ask the question in precise mathematical terms.

3. Oct 10, 2012

### skydivephil

Didnt Guth and Farhi do some work on this? I dont remember the reference so maybe somone else know about it. But Im pretty sure they wrot e apaper on this and Sean Caroll based his eternal cosmology model on it.

4. Oct 10, 2012

### Chronos

Yes, but, as twofish pointed out, it relies on assumptions that are unsupported by observation - like gravitational singularities..